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Cov txheej txheem tsim khoom noj & dej haus
Hauv cov txheej txheem tsim khoom noj thiab dej haus, ntau cov khoom siv raw ua kua, nrog rau cov kua txiv hmab txiv ntoo, kua txiv hmab txiv ntoo, cov khoom noj siv mis, cawv, thiab lwm yam, yuav tsum tau ua tiav.Suspended solids, sediment, thiab micro-organisms feem ntau muaj ...Nyeem ntxiv
